Updates to the command-line shell. Simplify the banner message. Add the
".save" command as an alias for ".backup". When starting with no arguments,
include a banner message warning that the database is transient and in-memory
and mention the ".open" command.

Updates to the command-line shell. Simplify the banner message. Add the
".save" command as an alias for ".backup". When starting with no arguments,
include a banner message warning that the database is transient and in-memory
and mention the ".open" command.
check-in: f5ad1e1b user: drh tags: trunk